DE112022001915T5 - TRANSPARENT HEATING DEVICE - Google Patents

Abstract

A transparent heater comprises: a substrate (2) transparent to visible light and having a surface (2a); and a conductive layer (3) disposed on one surface, transparent to visible light and containing an aggregate of carbon nanotubes. The conductive layer includes: a patterned portion (4) comprising a linear portion linearly extending in a first direction (D1) parallel to the one surface; and an unpatterned portion (5) which is a sheet-shaped portion bonded to the patterned portion in a second direction (D2) parallel to the one surface and orthogonal to the first direction and having a thickness smaller than that of patterned section in a third direction (D3) which is orthogonal to the one surface. The unpatterned portion has an orientation direction of the carbon nanotubes that defines less than 45 degrees with respect to the second direction, the orientation direction being measured by an orientation evaluation method using image processing on an electron microscope image.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2021-62595 , which was filed on April 1, 2021, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a transparent heater containing an aggregate of carbon nanotubes (CNTs).

TECHNICAL BACKGROUND

Patent Literature 1 discloses a transparent heater having a substrate having one surface and a conductive layer provided on one surface. The conductive layer contains an aggregate of CNTs. The conductive layer includes a patterned portion having a linear portion that linearly extends in a first direction and an unpatterned portion that is a sheet-shaped portion connected to the linear portion in a second direction orthogonal to the first direction. The unpatterned section is thinner than the patterned section.

STATE OF THE ART LITERATURE

PATENT LITERATURE

Patent literature 1: JP 2020-119744 A

SUMMARY OF THE INVENTION

In the conventional transparent heater described above, the patterned portion generates a larger amount of heat than the unpatterned portion because the patterned portion is thicker than the unpatterned portion. Therefore, the temperature of the unpatterned portion is lower than that of the patterned portion, and in the transparent heater, temperature unevenness occurs in a plane direction parallel to the one surface of the substrate. An object of the present disclosure is to provide a transparent heater capable of reducing temperature unevenness in a planar direction.

• ein Substrat, das für sichtbares Licht transparent ist und eine Oberfläche aufweist; und
• eine leitfähige Schicht, die auf der einen Oberfläche angeordnet ist, für das sichtbare Licht transparent ist und ein Aggregat von Kohlenstoffnanoröhren enthält,
• wobei die leitfähige Schicht umfasst: einen gemusterten Abschnitt, der einen linearen Abschnitt aufweist, der sich linear in einer ersten Richtung parallel zu der einen Oberfläche erstreckt; und einen ungemusterten, bzw. nicht gemusterten Abschnitt, der ein folienförmiger Abschnitt ist, der mit dem gemusterten Abschnitt in einer zweiten Richtung verbunden ist, die parallel zu der einen Oberfläche und orthogonal zu der ersten Richtung ist, und der eine geringere Dicke als der gemusterte Abschnitt in einer dritten Richtung aufweist, die orthogonal zu der einen Oberfläche ist, und
• wobei der ungemusterte Abschnitt eine Orientierungsrichtung der Kohlenstoffnanoröhren aufweist, die weniger als 45 Grad in Bezug auf die zweite Richtung definiert, wobei die Orientierungsrichtung durch ein Orientierungsbewertungsverfahren unter Verwendung einer Bildverarbeitung an einem Elektronenmikroskopbild gemessen wird.

To achieve the above object, according to one aspect of the present disclosure, a transparent heater includes:

• a substrate that is transparent to visible light and has a surface; and
• a conductive layer disposed on one surface, transparent to visible light and containing an aggregate of carbon nanotubes,
• wherein the conductive layer comprises: a patterned portion having a linear portion linearly extending in a first direction parallel to the one surface; and an unpatterned portion that is a sheet-shaped portion bonded to the patterned portion in a second direction parallel to the one surface and orthogonal to the first direction and having a smaller thickness than the patterned one Section in a third direction that is orthogonal to the one surface, and
• wherein the unpatterned portion has an orientation direction of the carbon nanotubes that defines less than 45 degrees with respect to the second direction, the orientation direction being measured by an orientation evaluation method using image processing on an electron microscope image.

Accordingly, compared to a case where the carbon nanotubes constituting the unpatterned portion are not oriented, heat is easily conducted from the patterned portion to the entirety of the unpatterned portion. Accordingly, the temperature difference between the approx patterned portion and the patterned portion can be reduced, and the temperature unevenness in the planar direction of the transparent heater can be reduced.

The parenthesized reference numerals attached to the respective constituent elements and the like indicate an example of a correspondence relationship between the constituent elements and the like and certain constituent elements and the like used in the embodiments described later are described.

BRIEF DESCRIPTION OF THE DRAWINGS

• 1 shows a top view of a transparent heating device according to a first exemplary embodiment.
• 2 shows a sectional view along a line II-II of 1 .
• 3 shows an electron microscope image of part III of 1 .
• 4 Fig. 10 is a sectional view showing a process of preparing a filter in a method of manufacturing a transparent filter according to the first embodiment.
• 5A Fig. 10 is a diagram showing a process of trapping CNTs in the method of manufacturing a transparent filter according to the first embodiment.
• 5B shows a diagram showing a flow or current of the CNT dispersion in a cavity section of a resist in the in 5A process shown.
• 5C 1 shows a diagram showing the flow of the CNT dispersion on an upper surface of a cap portion of the resist and the cavity portion in the FIG 5A process shown.
• 5D shows a diagram showing a conductive section formed by trapping the CNTs in the in 5A process shown is formed.
• 6A Fig. 12 is a diagram showing a part of a process of transferring the conductive portion to a transparent substrate in the method of manufacturing a transparent filter according to the first embodiment.
• 6B shows a diagram showing a process that follows the in 6A followed by the process shown.
• 7 shows a top view of a test specimen used in a test for examining the relationship between an orientation direction of CNTs and the ease of heat conduction.
• 8th shows a diagram showing the results of the test to investigate the relationship between the orientation direction of the CNTs and the ease of heat conduction.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure are described below with reference to the drawings.

(First embodiment)

A transparent heating device 1 in the 1 and 2 The illustrated embodiment is used as a heating device to ensure the function of an on-board sensor or a windshield of a vehicle. The transparent heating device heats the sensor or the windshield when icing, fogging or the like occurs on the sensor or the windshield. Accordingly, icing, fogging or the like is eliminated. The transparent heater is not limited to being installed in a vehicle, and may be installed in an object other than the vehicle, for example, a traffic light.

The transparent heater 1 includes a substrate 2 and a conductive layer 3. The substrate 2 has one surface 2a which supports the conductive layer 3 and the other surface 2b which faces the one surface 2a. The one surface 2a is a surface of the substrate 2 on the conductive layer 3 side. The one surface 2a is flat. In each drawing, a first direction D1 is a direction parallel to the one surface 2a. A second direction D2 is a direction parallel to that a surface 2a and orthogonal to the first direction D1. A third direction D3 is a direction orthogonal to the one surface 2a.

The substrate 2 is transparent to a desired visible light and has an electrical insulation property. The substrate 2 is made of a synthetic resin material (for example, PC or the like) or an inorganic material (for example, quartz glass or the like). PC is polycarbonate. The substrate 2 has a shape such as a foil, a film or a plate.

The conductive layer 3 is provided on one surface 2a of the substrate 2. The conductive layer 3 contains an aggregate of CNTs. The aggregate of CNTs mainly forms the shape of the conductive layer 3. When electrically conductive, the conductive layer 3 generates heat. The conductive layer 3 includes a plurality of patterned portions 4 and a plurality of non-patterned portions 5. Each of the plurality of patterned portions 4 and each of the A plurality of unpatterned portions 5 are arranged alternately in the second direction.

Each patterned portion 4 is a portion of the conductive layer 3 that includes a linear portion 4a linearly extending in the first direction D1. The linear portion 4a is a portion of the conductive layer 3 that protrudes from the substrate 2 in the third direction D3. The patterned sections 4 are arranged separately from each other in the second direction D2.

Each patterned section 4 has a width in the second direction D2 that is not visually recognizable to a human. The width of each patterned portion 4 is smaller than an average length of the CNTs or an average length of the bundles of CNTs. The thickness of each patterned portion 4 in the third direction D3 is a quantity that cannot be visually recognized. However, the thickness of each patterned portion 4 may have a size that can be visually recognized.

Each patterned section 4 has a base section 4b. The base portion 4b is a part of the patterned portion 4 on the base side, that is, a part of the patterned portion 4 on the substrate 2 side in the third direction D3. The base section 4b is continuous with the linear section 4a in the third direction D3 and is continuous with the unpatterned section 5 in the second direction D2.

Each of the unpatterned portions 5 is a film-shaped portion of the conductive layer 3 and is continuous with the patterned portion 4 in the second direction D2. That is, each of the unpatterned portions 5 has a planar shape extending in a direction parallel to the one Surface 2a extends. Each of the plurality of unpatterned sections 5 connects adjacent patterned sections 4 together. Among the plurality of unpatterned portions 5, an unpatterned portion positioned at the end in the second direction D2 is continuous with a patterned portion 4.

The thickness of each of the unpatterned portions 5 in the third direction D3 is smaller than the thickness of each of the patterned portions 4 in the third direction D3. Each unpatterned section 5 has a thickness that does not affect transparency, e.g. B. a thickness at which the transmittance or transmittance for visible light is 90% or more. The width of the unpatterned portion 5 in the second direction D2 is larger than the width of each patterned portion 4 in the second direction D2.

The CNTs are aligned or oriented in the plurality of patterned sections 4 and the plurality of unpatterned sections 5. In the patterned portion 4, the CNTs are aligned in a direction along the first direction D1. The direction along the first direction D1 means a direction that defines an angle of less than 45 degrees with respect to the first direction D1. In the unpatterned portion 5, the CNTs are aligned in a direction along the second direction D2. The direction along the second direction D2 means a direction that defines an angle of less than 45 degrees with respect to the second direction D2.

The formulation that the CNTs are aligned or oriented means here that the directions in which the CNTs extend and spread are aligned or coordinated with one another. The orientation direction of the CNTs is measured by an orientation evaluation method using image processing of an electron microscope image. The evaluation elements of the orientation through the orientation evaluation method include an orientation direction and an orientation magnitude. The orientation Direction and the orientation quantity are measured by the following method using an electron microscope and a measuring instrument that analyzes an image of the electron microscope and measures the orientation direction of the CNTs.

First, an electron microscope image of an object to be measured is obtained using a scanning electron microscope. In this case, as an example, the magnification is set to about x30 k, the acceleration voltage is set to about 1.5 kV, and the image is acquired at 3 locations.

Subsequently, the image obtained with the electron microscope is trimmed to cut out an arbitrary portion to have a size used for image processing to be performed next.

Then, image processing is performed using image processing software to obtain the orientation angle (i.e., the orientation direction) and the orientation size. An average value of the orientation angles obtained at three locations and an average value of the orientation quantities obtained at three locations are calculated. That is, the arithmetic mean of each of the obtained orientation angles and orientation quantities is calculated.

The “Non-destructive paper surface fiber orientation analysis program FiberOri8single03.exe (V. 8.03.)” is used as image processing software. This software is available at “http://www.enomae.com/FiberOri/index.htm”. In this software, the orientation angle and the orientation size are calculated by binarizing a microscope image and performing a Fourier transformation. The calculated orientation angle (i.e., the orientation angle (degrees)) indicates an angle defined relative to the left-right direction of the image. The calculated orientation magnitude (i.e. the orientation intensity) indicates the strength of the orientation. The reference size is represented by a numerical value of 1 or more. A numerical value in the range 1.0 to 1.1 does not provide any orientation. A numeric value in the range greater than 1.1 and less than 1.2 indicates that the orientation is present. A numerical value of 1.2 or more indicates strong orientation.

3 Fig. 12 shows an electron microscope image of the transparent heater 1 actually manufactured by the present inventors. In the patterned portion 4, the CNTs are arranged in a dense state. The width of the patterned section 4 is approximately 10 μm. The length of the CNTs and the length of the bundle of CNTs used here was 20 to 30 μm.

In the unpatterned section 5, the CNTs are arranged in a sparser or sparser state than in the patterned section 4. The width of the unpatterned section 5 is greater than 100 μm. The thickness of the unpatterned section 5 is about 1 to 10 nm. The diameter of the CNT used here is about 1 to 2 nm. The thickness of the unpatterned section 5 is close to the diameter of a single CNT and is very thin. Therefore, the visible light transmittance of the unpatterned portion 5 is high.

Table 1 shows the results of measuring the orientation angle and the orientation size of the CNTs of the patterned portion 4 by the orientation evaluation method described above. The orientation angle is an angle with respect to the first direction D1. [Table 1] Orientation size 1.18 1.17 1.17 Orientation angle -5 8th -1

As shown in Table 1, the orientation size of the patterned portion 4 was in a range of greater than 1.1 and less than 1.2, and thus it was confirmed that the CNTs were oriented. In addition, it was confirmed that the average value of the orientation angles of the patterned portion 4 was 0.7 and the orientation direction of the CNTs was a direction along the first direction D1.

Table 2 shows the results of measuring the orientation angle and the orientation size of the CNTs in the unpatterned portion 5 by the orientation evaluation method described above. [Table 2] Orientation size 1.33 1.31 1.33 Orientation angle 93 94 92

As shown in Table 2, the orientation size of the unpatterned portion 5 was 1.2 or more, and it was confirmed that the CNTs were highly oriented. In addition, it was confirmed that the average value of the orientation angles of the unpatterned portion 5 was 93°, and the orientation direction of the CNTs was a direction along the second direction D2.

Note that the patterned portion 4 in which the CNTs were not oriented was formed, and the orientation direction and the orientation size of the CNTs were measured by the orientation evaluation method described above. The measurement results for this case are shown in Table 3. [Table 3] Orientation size 1.06 1.02 1.05 Orientation angle 63 -10 -13

As shown in Table 3, the orientation size in this case was in the range of 1.0 to 1.1. Since the CNTs are not oriented, the orientation angle was not uniform.

Next, a method of manufacturing the transparent heater 1 of the present embodiment will be described. First, as in 4 shown, a process for preparing a filter 11 covered with the resist 12 is carried out.

The filter 11 is used to separate the CNTs from the dispersion medium and to capture the CNTs. The filter 11 is a porous body with a plurality of pores. The size of the plurality of pores is a size that allows the dispersion medium to pass through but does not allow the CNTs to pass through. A membrane filter, for example, is used as the filter 11.

The resist 12 is a covering material that covers a surface of the filter 11. The resist 12 is a dense body that does not have holes. The resist 12 has cavity portions 12a for forming the plurality of patterned portions 4 and cap portions 12b covering the filter 11. The cavity portions 12a are located in areas where the plurality of patterned portions 4 are to be formed in a region on one surface of the filter 11. The design or layout of the cavity portions 12a is the same as the layout of the plurality of patterned portions 4. The width of the cavity portion 12a, which corresponds to the width of the patterned portion 4, is smaller than the average length of the CNTs or the average length of the bundles of CNTs (i.e. the bundle). The cover portions 12b are located in areas where the unpatterned portions 5 are to be formed in the region on a surface of the filter 11.

Subsequently, a process of trapping CNTs on one surface of the filter 11 is performed. In this process, as in 5A shown, a CNT dispersion is supplied in the direction of the filter 11 from a tube 13, which is arranged in the third direction D3 opposite the filter 11 with respect to the resist 12. The CNT dispersion contains CNTs and a dispersion medium. The dispersion medium is a gas for dispersing the CNTs. The dispersion medium can be a liquid.

In this case, the tube 13 and the filter 11 are arranged at positions such that the flow of the CNT dispersion medium from the tube 13 toward the filter 11 becomes the flow along the first direction D1. In particular, as in 5B shown, the tube 13 and the filter 11 are arranged at different positions in the first direction D1. Therefore, the CNT dispersion flows as indicated by arrows in 5B indicated, from the tube 13 toward the filter 11 in oblique directions including the third direction D3 and the first direction D1.

As in 5C shown, when the velocity of the CNT dispersion flows, or the flows of the CNT dispersion, flowing through the cavity portions 12a are high, CNT dispersion flows, which flow from the central side of the cover portion 12b toward the cavity portions 12a are formed on the surface of the cover portion 12b. The CNT dispersion flows directly from the central side of the cover portion 12b toward the cavity portions 12a are flows along the second CNT dispersion direction D2. Therefore, the speed of the CNT dispersion flow flowing through the cavity portion 12a is set to the speed at which the CNT dispersion flow is formed along the second direction D2 on the surface of the cover portion 12b. Specifically, at least one of setting the speed of flow of the CNT dispersion from the tube 13 to a high value or setting the width of the cavity portion 12a in the second direction D2 to a narrow value is performed.

The CNTs are trapped in the cavity portions 12a and on the surface of the cap portion 12b of the resist 12. As a result, as in 5D shown, the conductive layer 3 with the patterned sections 4 and the unpatterned sections 5 is formed on one surface of the filter 11. In this case, the CNT dispersion in the cavity portions 12a flows along the first direction D1. Therefore, the CNTs constituting the linear portion 4a of the patterned portion 4 are oriented in the direction along the first direction D1. The CNT dispersion flows on the surface of the cover portion 12b along the second direction D2. Therefore, the CNTs constituting the unpatterned portion 5 are oriented in the direction along the second direction D2.

Subsequently, a process of transferring the conductive layer 3 to the substrate 2 is performed. As in 6A shown, one surface 2a of the substrate 2 is brought into contact with the conductive layer 3. As in 6B shown, the filter 11 and the resist 12 are separated from the substrate 2. As a result, the conductive layer 3 is formed on one surface 2a of the substrate 2. In this way, the transparent heating device 1 is produced.

Next, the relationship between the orientation direction of the CNTs and the ease of heat conduction in the film composed of the CNTs is described. The present inventors studied the difference in heat conduction between four films with different orientation directions of CNTs.

Each of the four films is formed on a PC substrate. The thickness of the four films is uniform or uniform. As in 7 shown, each of the four films has a shape that includes a rectangular first region 21 and a square second region 22. The first region 21 has a longitudinal direction along an x-direction and a transverse direction in a y-direction orthogonal to the z-direction. The second region 22 is connected to the central portion of a longitudinal side of the first region 21. The second region 22 protrudes from the first region 21 in the y direction.

A length L1 of the first region 21 in the x direction is 50 mm. A length L2 of the first region 21 in the y direction is 20 mm. A length L3 and a length L4 of the respective sides of the second region 22 is 10 mm.

The four films each have the orientation directions 0°, 45°, 90° and random with respect to the x-direction. The direction that defines 0° with respect to the x direction is the x direction. The direction that defines 90° with respect to the x direction is the y direction. The orientation of the CNTs is the same throughout an entire film. Each of the four films is cut from the same film in which the CNTs are oriented in one direction. The orientation sizes of the films measured using the orientation evaluation method described above were 1.12, 1.13 and 1.20.

The electrodes 23 and 24 are formed at opposite ends of the first region 21 in the x direction. When a current is caused between the electrodes 23 and 24, the current flows through the first region 21 and the first region 21 generates heat. However, no current flows in the second region 22 and the second region 22 does not generate heat. When the first region 21 generates heat, the heat is transferred from the first region 21 to the second region 22 by conduction. Therefore, the current was caused to flow between the electrodes 23 and 24, and the temperature at a point B in the second region 22 was measured when the temperature at a point A in the first region 21 reached about 35 ° C. In this way, the ease of heat transfer in the y-direction of each film was examined. The room temperature at this time was around 25 °C. The measurement results are in Table 4 and 8th shown. [Table 4] Orientation direction Temperature point A [°C] Temperature point B [°C] 0° 35.1 25.7 45° 35.1 26.9 90° 35.0 28.1 No orientation 35.0 26.7

As shown in Table 4, the temperature of point B was the lowest when the film had an orientation direction of 0°, and the temperature of point B was the highest when the film had an orientation direction of 90°. The temperature of the point B of the film having the orientation direction of 45° was almost the same as the temperature of the point B of the film having no orientation. As in 8th shown, the temperature of point B was higher than that of the film without orientation when the orientation direction is greater than 45 degrees and equal to or less than 90 degrees.

Accordingly, it was found that heat transfer in the y-direction is more likely to occur when the orientation direction is greater than 45° and equal to or less than 90°, compared to the case where the CNTs have no orientation. The orientation direction that is greater than 45° and equal to or less than 90° is the same as the orientation direction that defines an angle of less than 45° with respect to the y-direction.

The effects of the transparent heater 1 of the present embodiment are described below. The transparent heater 1 of the present embodiment is compared with a transparent heater 1 of a comparative example. The transparent heater 1 of the comparative example differs from the transparent heater 1 of the present embodiment in that CNTs are not oriented in each of the patterned portions 4 and the unpatterned portions 5. Other configurations of the transparent heater 1 of the comparative example are the same as those of the transparent heater 1 of the present embodiment.

In the transparent heater 1 of the comparative example, the conductive layer 3 generates heat by electrical conduction. However, due to the difference in thickness between the patterned section 4 and the unpatterned section 5, the amount or extent of heat generation between the patterned section 4 and the unpatterned section 5 is different. That is, since the patterned portion 4 is thicker than the unpatterned portion 5, the patterned portion 4 generates more heat than the unpatterned portion 5. Therefore, the temperature of the unpatterned portion 5 is lower than that of the patterned portion 4, and temperature unevenness occurs a flat direction parallel to one surface 2a of the substrate 2. The temperature non-uniformity becomes more noticeable the larger the interval between the adjacent patterned sections 4, i.e. H. the greater the width of the unpatterned section 5 to ensure the transparency of the conductive layer 3.

In the transparent heater 1 of the present embodiment, the CNTs constituting the unpatterned portion 5 are oriented in the direction defining the angle of less than 45 degrees with respect to the second direction D2. As described above, when the orientation direction of the CNTs defines the angle of less than 45 degrees with respect to the y-direction, the heat transfer in the y-direction is more likely to occur than when the CNTs are not oriented. Therefore, the unpatterned portion 5 easily conducts heat in the second direction D2 compared to the transparent heater of the comparative example. That is, the heat is easily conducted from the patterned section 4 to the entire unpatterned section 5. As a result, the temperature difference between the patterned portions 4 and the unpatterned portions 5 can be reduced, and the temperature unevenness in the planar direction of the transparent heater 1 can be reduced.

• (1) Die CNTs, die den linearen Abschnitt 4a des gemusterten Abschnitts 4 bilden, sind in der Richtung orientiert, die einen Winkel von weniger als 45 Grad in Bezug auf die erste Richtung D1 definiert. Der Fluss fließt leicht in der Orientierungsrichtung der CNTs. Daher kann der elektrische Widerstand des gemusterten Abschnitts 4 im Vergleich zu der transparenten Heizeinrichtung 1 des Vergleichsbeispiels verringert werden.
• (2) Der ungemusterte Abschnitt 5 ist direkt mit dem gemusterten Abschnitt 4 verbunden, ohne dass eine Haftschicht dazwischen angeordnet ist. Dies erleichtert eine Wärmeleitung von dem gemusterten Abschnitt 4 zu dem ungemusterten Abschnitt 5 im Vergleich zu einem Fall, in dem der gemusterte Abschnitt 4 und der ungemusterte Abschnitt 5 über eine Haftschicht verbunden sind.
• (3) Die Breite des gemusterten Abschnitts 4 in der zweiten Richtung D2 ist schmaler als die Durchschnittslänge der CNTs oder die Durchschnittslänge der Bündel von CNTs. Dementsprechend können die CNTs, wenn die CNT-Dispersion durch den Filter 11 gefiltert wird, der mit dem Resist 12 bedeckt ist, um den linearen Abschnitt 4a des gemusterten Abschnitts 4 zu bilden, in der ersten Richtung D1 oder einer Richtung nahe der ersten Richtung D1 orientiert sein.

With the transparent heater 1 of the present embodiment, the following effects are achieved.

• (1) The CNTs constituting the linear portion 4a of the patterned portion 4 are oriented in the direction defining an angle of less than 45 degrees with respect to the first direction D1. The flow flows easily in the orientation direction of the CNTs. Therefore, the electrical resistance of the patterned section 4 can be reduced compared to the transparent heater 1 of the comparative example.
• (2) The unpatterned portion 5 is directly bonded to the patterned portion 4 without interposing an adhesive layer. This facilitates heat conduction from the patterned portion 4 to the unpatterned portion 5 compared to a case where the patterned portion 4 and the unpatterned portion 5 are bonded via an adhesive layer.
• (3) The width of the patterned portion 4 in the second direction D2 is narrower than the average length of the CNTs or the average length of the bundles of CNTs. Accordingly, when the CNT dispersion is filtered by the filter 11 covered with the resist 12 to form the linear portion 4a of the patterned portion 4, the CNTs can be in the first direction D1 or a direction close to the first direction D1 be oriented.

(Other embodiments)

• (1) In the embodiment described above, the CNTs constituting the linear portion 4a of the patterned portion 4 are oriented. However, the CNTs that form the linear section 4a may also have no orientation. Even in this case, the temperature unevenness in the planar direction of the transparent heater 1 can be reduced.
• (2) In the above-described embodiment, the patterned portions 4 and the unpatterned portions 5 are formed simultaneously. Accordingly, the patterned sections 4 and the unpatterned sections 5 are directly continuous with each other. However, the patterned portions 4 and the unpatterned portions 5 may be formed separately and then bonded together via an adhesive layer.
• (3) In the above-described embodiment, in the process of trapping the CNTs, the tube 13 and the filter 11 are arranged at different positions in the first direction D1. Accordingly, the CNT dispersion flows through the cavity portions 12a of the resist 12 along the first direction D1. However, apart from the tube 13, a supply opening for supplying a gas such as nitrogen gas is arranged next to the resist 12. The gas flows from the supply port in a direction along the first direction D1. In this way, the CNT dispersion supplied from the tube 13 can be caused to flow through the cavity portion 12a of the resist 12 along the first direction D1.
• (4) The present disclosure is not limited to the above description of the embodiment and may be appropriately modified, thus including various modifications and variations in equivalent areas. The embodiments described above are not independent of each other and may be appropriately combined unless the combination is obviously impossible. In each of the embodiments described above, individual elements or features of a particular embodiment are not necessarily essential unless it is expressly stated that the elements or features are essential or unless the elements or features are obviously essential in principle . Further, in each of the above-described embodiments, when reference is made to numerical values such as the number, quantity, range, and the like of the constituent elements of the embodiment, the present disclosure is not limited to the specific number unless the numerical values are express essential, or the numerical values are obviously fundamentally limited to a certain number, and the like. Furthermore, in each of the above-described embodiments, when referring to the material, shape, positional relationship and the like of the components and the like, the components are not limited to the material, shape, positional relationship and the like except in the case where the components are expressly specified, and except in the case where the components are fundamentally limited to a specific material, a specific shape, a specific positional relationship and the like.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 202162595 [0001]
• JP 2020119744 A [0004]

Claims (4)

Transparent heating device, with a substrate (2) transparent to visible light and having a surface (2a); and a conductive layer (3), which is arranged on one surface, is transparent to visible light and contains an aggregate of carbon nanotubes, wherein the conductive layer comprises: a patterned portion (4) including a linear portion linearly extending in a first direction (D1) parallel to the one surface; and an unpatterned portion (5) which is a film-shaped portion connected to the patterned portion in a second direction (D2) parallel to the one surface and orthogonal to the first direction, and a thickness smaller than that of the patterned one Section in a third direction (D3) which is orthogonal to the one surface, and wherein the unpatterned portion has an orientation direction of the carbon nanotubes that defines less than 45 degrees with respect to the second direction, the orientation direction being measured by an orientation evaluation method using image processing on an electron microscope image. Transparent heating device after Claim 1 , wherein the linear portion of the patterned portion has an orientation direction of the carbon nanotubes that defines an angle of less than 45 degrees with respect to the first direction, the orientation direction being measured by the orientation evaluation method. Transparent heating device after Claim 1 or 2 , where the unpatterned section is directly connected to the patterned section. Transparent heating device according to one of the Claims 1 until 3 , wherein the patterned portion has a width in the second direction that is smaller than an average length of the carbon nanotubes or an average length of bundles of the carbon nanotubes.

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